ValidateAddress.class.php

<?php

	/**
	 * Cryptocurrency address validator
	 */
	class Premium_ValidateAddress
	{

		public function _valid_btc( $ADDRESS )
		{
			$addr = $this->__decode_base58( $ADDRESS );
			if (strlen($addr) != 50)
	          	return false;

	        $check = substr($addr, 0, strlen($addr) - 8);
	        $check = pack("H*", $check);
	        $check = strtoupper(hash("sha256", hash("sha256", $check, true)));
	        $check = substr($check, 0, 8);

	        return $check == substr($addr, strlen($addr) - 8) ? 'btc' : false;
		}

		public function _valid_litecoin( $ADDRESS )
		{
			return preg_match('/^[LM3][a-km-zA-HJ-NP-Z1-9]{26,33}$/', $ADDRESS) == 0 ? false : 'ltc';
		}

		public function _valid_eth( $ADDRESS )
		{
			if (!preg_match('/^(0x)?[0-9a-f]{40}$/i',$ADDRESS))
				return false;
			elseif (!preg_match('/^(0x)?[0-9a-f]{40}$/',$ADDRESS) || preg_match('/^(0x)?[0-9A-F]{40}$/',$ADDRESS))
				return 'eth';
			else
				return $this->_valid_checksum( $ADDRESS );
		}

		private function _valid_checksum( $ADDRESS )
		{
			$address = str_replace('0x','',$ADDRESS );
			$addressHash = hash('sha3',strtolower( $ADDRESS ));
			$addressArray=str_split( $ADDRESS );
			$addressHashArray=str_split($addressHash);

			for($i = 0; $i < 40; $i++ )
			{
				if (
						(intval($addressHashArray[$i], 16) > 7 &&
						strtoupper($addressArray[$i]) !== $addressArray[$i]) ||
						(intval($addressHashArray[$i], 16) <= 7 &&
						strtolower($addressArray[$i]) !== $addressArray[$i])
					)
						return false;
			}
				return 'eth';
		}

		private function __encode_hex( $DEC )
	    {
	        $hexchars = "0123456789ABCDEF";
	        $return = "";

	        while (bccomp($DEC, 0) == 1)
	        {
	            $dv = (string) bcdiv($DEC, "16", 0);
	            $rem = (integer) bcmod($DEC, "16");
	            $DEC = $dv;
	            $return = $return . $hexchars[$rem];
	        }

	        return strrev($return);
	    }

	    private function __decode_base58( $BASE )
	    {
	        $base58chars = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
	        $return = "0";

	        for ($i = 0; $i < strlen($base58); $i++)
	        {
				$current = (string) strpos($base58chars, $base58[$i]);
				$return = (string) bcmul($return, "58", 0);
				$return = (string) bcadd($return, $current, 0);
	        }

	        $return = $this->__encode_hex($return);

	        //leading zeros
	        for ($i = 0; $i < strlen($BASE) && $BASE[$i] == "1"; $i++)
				$return = "00" . $return;
	        if (strlen($return) % 2 != 0)
	        	$return = "0" . $return;

	        return $return;
	    }
	}